Forbidden rotation reversing, position control servosystem



May 24, 1960 H. s. KlRscHBAuM 2,933,154

FORBIDDEN RoTATIoN REvERsING, POSITION CONTROL sERvosYsTEM Filed July:51, 1957 FIG. 2

,4o Gun, sYNcHRos is! 4: a 2 4 g L aalawolmaloa Nouns mamon fmfe s wlmg\ulglm |o H N I N y l 1:1 l: O z v 1 v r?" ams Moo IV uns ma c: fr E m oa 4 E 'I' c :e 0"

a lll D v l t HERBERT s. KlRscHBAuM w INVENTOR.

v 1 asiawounalod Noulsod une BY FORBIDDEN ROTATION REVERSING, POSITIONCONTROL SERVOSYSTEM Herbert S. Kirschbaum, Columbus, Ohio, assgnor, bymesne assignments, to the United States of America as represented by theSecretary of the Navy Filed July 31, 1951, ser. No. 675,507

a claims. (ci. V51e- 29) The present invention relates to an automaticsynchronizer for controlling the'training of a gun mechanism and moreparticularly to an automatic stop avoiding synchronizing circuit.

In the prior art, there are numerous types of automatic synchronizersavailable to synchronize the training position of a gun with theposition indicated at some remote control station. In these priorsystems, the gun rotates or trains through the shortest path tosynchronize with the indicated position of the control station unlessotherwise prevented by a stop or limit which is between the actual gunposition and its ultimate desired position designated by the controlstation. However, if the gun can not synchronize because a stop or limitintervenes, the prior art systems must be deenergized and the gunrotated manually to a position such that the automatic synchronizationcan take place unhindered.

The present invention is a system of connecting a gun positionpotentiometer and a stop position potentiometer so that the abovementioned disadvantages are overcome and that the gun is alwayssynchronized with a control station.

An object of the present invention is the provision of a system thatautomatically synchronizes a gun with a control station through theshortest path of training of the gun regardless of the initial positionof the gun relative to the position requested by the control stationunless the shortest path is barred by a limit stop.

Another object of the present invention is the provision ofautomatically synchronizing a gun to the control station through thelonger path of training if the shortest path of training of a gun isbarred by a limit stop.

A further object of the invention is to provide synchronization of thegun with limit stops set as far apart as 720 (Lt-360).

A further object of the invention is the provision of synchronizing agun of minimum training angle when the control station is indicating aposition within the allowable gun training range.

A still further object of the invention is to provide synchronization ofthe gun within the dead zone of the control station potentiometer.

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawing wherein:

Fig. 1 is a schematic diagram of a suitable form of the automaticsynchronizer circuit.

Fig. 2 is a diagram showing the details of the control stationpotentiometer.

In Fig. l, the stop avoiding synchronizing circuit is shown as havingthree potentiometers 61, 11, and 21, and three relays R3, R4 and R5.

The potentiometers are connected in parallel between e, positive and anegativek voltage source. The gun po- 2,93,l54 Patented May 24, 1960sition potentiometer 61 with its slider '62 is geared to the gun in sucha manner that the slider 62 traverses the entire potentiometer when thegun rotates a total of two revolutions, (i360).

The second potentiometer referred to as the stop position potentiometer11, has two movable sliders 12 and 13. The sliders 12 and 13 are set tocoincide with the automatic cut-ott position beyond which the gun cannot train except manually.

A desired gun training position is determined at the control station.This new training position is indicated in the synchronizing circuit bythe third potentiometer, that is the control station potentiometer 21,in conjunction with a split pick-up strip 26. The split pick-up strip 26is made up of two parts, the clockwise section 27 and thecounterclockwise section 28. The control station potentiometer 21 hastwo sliders 24 and'25 spaced 180 apart. The sliders 24 and 25 as shownin Figs. ll

and 2 make contact between the control station potenti-l ometer 21 andthe split pick-up strip 26 in such a manner that each slider contactsonly one section of the strip at any instant. The sliders 24 and 25 canrotate continuously and provide electrical contact over as much of the360 of the control station potentiometer 21 as possible and are drivenfrom the control station by means of a synchromotor and suitable gearingto give exactly one control station potentiometer revolution for twocontrol station revolutions. However, the sliders 24 and 25 must notshort the sections 27 and 28 together.

Relays R3, R4, and R5 with their contacts connect the threepotentiometerstogether. Relays R3 andR4 are made polarity sensitive byrectiiiers 14 and 15, respectively. Relay R3 has two contacts; R31normally closed and R32 normally opened. Relay R4 has two contacts; R41normally closed and R42 normally opened. Relay R5 has four contacts; R51normally closed, R52, R53 and R51-tl normally opened. Due to the actionof either rectifier 14 or 15, one of the relays R3 and R4 operate whenthe position of either slider 24 or 25vindicates a potential differenceover the potential at one of the sliders 12 and 13. This potentialdifference between potentiometer 21 and potentiometer 11 through one ofthe pick-up strips causes one of the relays to operate therebyconnecting a potential from the other pickup strip to the right side ofrelay R5. The other side of relay R5 has a potential of a valuedependent upon the position of slider 62 of the gun positionpotentiometer. When the potential across relay R5, determined by thedilerence between the potential of the other pick-up strip and thatindicated by the slider 62, is great enough; the

. relay R5 will be energized causing the relay contacts of R5 tooperate, cutting out demodulator 70, and thereby applying this samepotential across relay R5 and its associated polarity to the D C.amplifier 75.

There are three possible desired gun train positions as called for bythe control station which might arise in the course of synchronizing agun as noted by the A, B and C positions of sliders 24 and 25.

in position A both sliders 24 and 25 lie within the region between thestop position sliders 12 yand 13 on the stop position potentiometer asshown in Fig. 1. The potential on the control station potentiometer 21at position A of slider 24 is less negative than the potential on stopposition potentiometer 11 at slider 13 so that relay R4 does not operatedue to the inaction of rectier 15. In the same manner, the potential onthe control station potentiometer 21 at slider 25 position A is lesspositive than the potential on the stop position potentiometer 11 atslider 12 and consequently relay R3 does not operate due to the inactionof rectifier 14. In this position A, it will be apparent that nopotential is applied to relayA R5`and that the gun synchronizes normallythrough the action of the error-measuring synchros, the demodulator 70,the amplier 75, generator 78 and motor 80 to drive the gunto the newposition.

At position Bone of the sliders of the control station potentiometer 21is beyond the lcounterclockwise stopV position of slider 12 of the stopposition potentiometer 11. In this position B, the shortest physicalpath for the lgun to synchronize would be a counterclockwise one,providedV there is no automatic cut-oifs or limit stops betweenthe gunand control station.Y However, it is seen from'Fig. 1 that if thel guncontinues to move in the counterclockwise direction it would runv intothey automatic cut-off before vreaching the desired position.

The circuit ofthe invention as shown in Fig, l operates at position Basfollows. Relay R4 remains deenergized duetothe' inaction ofthe rectifier15,but relay R3 is now" energizedl since the potential differencebetween point 7 on the pick-up section 28 and slider 12 has a valuewhich allows current to flow` through the rectifier 14. This is nowpossible since contact 25 at position B on control station potentiometer21 indicatesa greater potential than the potential at. slider12 on stopposition potentiometer 11'. Upon the energization of relay R3, contactR31 is opened and R32 is closed. Upon lthe closing of contact R32, thenegative potential from point 8 on the=clockwise section 27l isapplied.through,l contact R32-and` closed contact .R41 torelay R5. Since the gunisVI still at theprevious position, the gun position potentiometerindicates'. a certain potential atv slider 62. The potential.differencebetween, slider 62 and section 27 causes current to ow throughrelay R5 operating the relay R5. contacts.A These contacts `disconnectthe vdemodulator 70from the amplier 75 and connect to the amplifier thissame potential difference which is proportional to the angle between thegun and slider on the clockwise section 27 on the control stationpotentiometer. This potential differencewhich is applied to the ampli-rlier and subsequently tothe generator and motor, is of such polarity asto cause the gun to move inthe clockwise direction. As the gun moves inthe clockwise direction, the potential at slider 62 approaches thepotential of slider 24 at position B, whereby the potential across relayR5 decreases until relay R5 finally is deenergized. At this time, thegun is in position near enough to the new desired position as indicatedbycontrol station potentiometer y,21 that normal synchronization cantake place.

At position C, one of thefsliders of the control stationpotentiometer'is in position on. thev clockwise section 27 beyondtheclockwise-stop position of slider 13 on thestop.position'potentiometer 11. The operation in position C of thepreferred embodiment of the invention as shown in Fig. 1 isas follows.Relay R4 is now energized since the potential at point 8 isr greaterthan the potential at slider 13 on the stop position potentiometer 11,that is, greater in a negative sense so that a current can now flowthrough rectifier 15. Relay R3 is deenergized since rectifier 14 does.not allow any cur- Y rent to pass through it. VUpon .the operation ofrelay R4, contact R41 opens and contact R42 closes thereby applying apotential from point 7 through contact R42 and through contact R31 torelay R5. A potential difference which is proportional to the anglebetween the gun as notedby the position of slider 62 on gun positionpotentiometer andi the slider on the counterclockwise section 28 on thecontrol station potentiometer operates relay R5 hereby disconnecting thedemodulator 70 from therl amplifier 75 and feeds this potentialdifference to the amplifier.

This potentialA diierence is of suchk polarity that the gun; moves inthe clockwise direction. vAsthe gun so moves, the potential across relayR5 decreases until relay R51 nally drops out.` Atvthistime, the gun isnear enough to the desired control station position that it willsynchronize normally.-

A similar sequence of operations will also take place if the gunposition slider indicates a position on the clockwise portion of thepotentiometer 61. In this case, the circuit operates as before to detectthe presence of the stop in the synchronizing path of the gun andprovides the signal to the amplilierto move the gun in a direction toavoid the stop.

Under certain gun empla'cement conditions, the training range of agunmay have'l the requirement that the minimum angle `between theautomatic` cut-offs. be only A and consequently more than two-thirds ofthe full 360 of train is forbidden to the gun.. Thelimited positions areindicated by D inFig. 1. In this case if the sliders 24 and 25' are inposition A, then each slider of the control station potentiometer isbeyond the allowable region of operation of the gun. Both relays R3 andR4 are energized and therefor no potential is applied across relay R5.The gun during normal synchronizing is stopped by one of the automaticcutols. Synchronization can take place only if one of the slidersv on,the control station potentiometer is brought within the allowable gunposition training rangeas would Ibe the case at' position B or Cofthe-sliders of the controlv station potentiometer. y

In order to avoid a 2 to 3- dead zone between the ends ofy thecontrol-station potentiometer and the 'ends of the pick-up sections,a--cam-operated vswitch R6 is connected-between-.relayfRS andtheycenter'rtap of the control i station 'potentiometer-1 y,at` point 9.vWhen the sliders 24 and 25 arefwithin the-dead zoneneither relay R3 norrelay R4' isl energized'. By the-incorporation ofk theswitch Rlwhichcloses when the sliders arerin the dead zone,.a potential willbe appliedacross relay R5.'

One modification of. the. embodiment of the invention shown inrFig.,1Vwould be. to have cam-operated toggle switchesk actuated by the shaft ofthe ycontrol station potentiometer instead ofthe illustratedv split'pick-up strip. An. additional modification would be ,toV replacetherelays R3 and R4 and theirassociated rectiiiers 14V and: 15l`bypolarized relays. Y

Obviously many modifications and variations; of the present inventionare-possible in the light of the above teachings. It is Vtherefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. A stop avoiding synchronizing circuit having first means VVforindicating av potential` representative of,r the actual gun position,secondk means for indicating'a potential representative ofL the:automatic'cutf-oiv position of a gun beyond which the gun cannottrain,'third means for4 indicating a new vposition that thegunAautomatically trains to, a first relay mechanism, a second relaymechanism, saidsecond means connected to saidA thirdrmeans through saidrstrelay mechanism,l `said third means connected to saidfirst meansthrough. said first and second relay mechanism, saidV third meanshavingindicating means for indicating a first potential on4 said third meansgreater than the potential on said second means whereby saidy firstrelay mechanism is energizedand a second potential from said third meansis connected' to said second relay mechanism thereby causing said secondrelay mechanism to operaterand to establish a potential differencebetween said first means and said third means proportional to the anglebetweenrthergunv andthe indicating means of said third means to controlthe training of the gun in a directionaway from the automatic cut-offposition. Y Y

2. A stop avoiding gun training synchronizing circuit comprising firstmeans for establishing a potential representative of the actual guntraining position, second means for establishing potentialsrepresentative of the automatic cut-off positions of the gun, thirdmeans for establishing potentials representative of a ldesired guntraining position designated by a control station, said third'meansincluding aV splitpickup strip anda posunmhllr tentiometer with twosliders placed 180 apart, said split pick-up strip comprising aclockwise section and a counterclockwise section, each of said slidersmaking contact between said potentiometer and one of said sections ofsaid split pick-up strip, a pair of polarized operating means, each ofsaid sections connected to said second means through one of saidpolarized operating means, said second means and one of said sliders ofsaid potentiometer determining through one of said sections theoperation of one of said polarized operating means, make and breakmeans, switch means, make and break means connected between saidsections and said switch means, said switch means connected between saidfirst means and said make and break means, said one of said polarizedoperating means establishing an electrical connection through said makeand break means from the other of said sections to said switch means andsaid first means whereby the first and third means determine a potentialdilerence and its polarity proportional to the angular differencebetween the actual gun training position and the desired gun trainingposition and operates said switch means thereby applying said potentialdifference to drive the gun to the desired position in a trainingdirection away from the automatic cut-off position.

3. A system for automatically synchronizing a gun in training positionwith a desired position indicated at a control station comprising avoltage source, a gun position potentiometer, a control stationpotentiometer, and a stop position potentiometer connected in parallelacross said voltage source, said gun position potentiometer having aslider indicating a potential representing the position of the gun, asplit pick-up strip associated with said control station potentiometer,said control station potentiometer having two sliders placed 180 apartwhich ride on said split pick-up strip, said stop position potentiometerhaving sliders set to coincide with the automatic cut-o6 position beyondwhich the gun cannot train, a pair of relays, a third relay, said stopposition potentiometer connected from its sliders through said pair ofrelays and said split pick-up strip to said control stationpotentiometer and through the contacts of said pair of relays to saidthird relay to said gun position potentiometer, said third relayconnected between the slider of said gun position potentiometer and thecontacts of said pair of relays, a generator, a motor, an amplifier, ademodulator coupled to said amplifier supplying current to the fieldcoil of said generator, said motor for training the gun connected to theoutput of said generator, contacts of said third relay connected betweensaid third relay, said demodulator, and said amplifier, whereby one ofthe pair of relays operates to connect across the third relay apotential difference proportional to the angle between the gunpotentiometer slider and the other slider of said control stationpotentiometer in response to one of the sliders of the control stationpotentiometer indicating a desired position beyond the automatic cut-offposition as indicated by one of the sliders of the stop positionpotentiometer to cause the relay contacts of the third relay todisconnect the demodulator from said amplifier and to substitute thereinsaid potential difference to move the gun in a direction to the desiredposition thereby avoiding the automatic cut-of position.

References Cited in the tile of this patent UNITED STATES PATENTS2,583,058 Libman Jan. 22, 1952 2,750,553 Anderson June 12, 19562,767,361 Bloomquist et al. Oct. 16, 1956

